This book is continuation of PERCY JACKSON AND THE SEVEN SEIZED. Percy discovers that Pandora's box, or pithos, has been stolen from Hestia's guardianship. He and the original gang, consisting of Annabeth, Grover, Thalia, and Luke, travel to recover it but when everything seems doomed, they discover a master plot that might very well mean the end of civilization. Rated T.

This is the beginning of the story of a quest Percy goes on when everyone important in Percy's life disappears from Camp. The war god, Ares has thrown down the gauntlet and Percy, Thalia, Nico, and Clarisse must go on a quest to defeat him. The gods must go on their own quest to save the demigods and the horrible role that Ares played in the Gaean War come to light.